This invention relates to ventilated grain bin roof ribs. Grain bins often have sheet metal roofs made of metal sheets with overlapping stepped roof ribs to provide strength and rigidity. Typically, these grain bin roofs also are ventilated with J hatches, which are covered air ports in the roof which allow air to flow between the bin and the atmosphere. These J hatches are very common, but are well known to cause problems of snow and/or debris accumulation above the J hatch. This can result in unwanted and potentially damaging excess weight on the grain bin roof, as well as creation of a rust or corrosion prone area.
U.S. Pat. No. 7,338,359 described a grain bin roof rib system which includes a double ventilated wall rib system which provides a void for retaining therein a sliding air valve member. While this design has some benefits, it has several drawbacks as well.
The void for retaining the sliding air valve member could be prone to accumulating debris (dust, dirt, seeds, insects, etc.) especially when the grain bin blower is turned off and any debris located between the two ventilated walls of the rib could settle into and fill the gap between the two walls. Emptying these voids or gaps could be a non-trivial task. The full double wall design also consumes a large amount of metal for each roof and increases weight over many prior art ribbed roof systems.
Consequently, there exists a need for improved grain bin ventilation systems and structures which do not exhibit the shortcomings of such prior art systems.